Centralizer for drill steels



, 1933- J. I. HULISHIZER 2,141,716

CENTRALIZER FOR DR ILL STEEL-S Filed Oct. 2, 1957 H! '5 ATTORNEY.

Patented Dec. 27, 1938 CENTBALIZER FOR DRILL STEELS Joseph I. Hulshizer;

to lngersollltand Company, "a corporation of New Jersey Stewartsville, N. .L, assignor Jersey City, N. L,

Application October 2, 1937, Serial No. 166,953

6 Claims.

This invention relates to rock drills, and more particularly to a centralizer fora drill steel actuated by a rock drill of the hammer type.

In operations requiring the drilling of horizontal holes it is diilicult to maintain the cutting end of the drill steel in coaxial alignment with the rock drill, particularly when starting a hole on uneven rock surfaces. The bit end of the drill steel describes a gyratory movement and often strikes against the rock with sufiicient force to break the cutting wings.

This erratic action of the drill steel may be, in part, caused by the flexibility of its body portion but has been found to be mainly due to the natural clearances between the drillsteel and the chuck elements of the rock drill into which the shank end of the drill steel extends. Although these clearances are minimized to practical limits their cumulative effect nevertheless permits the working implement to decline from the axis of the rock drill. Thus, as the drill hole proceeds this misalignment causes undue friction between the bit and the rock and speedily reduces the gauging surfaces of the bit to a point requiring reconditioning. Excessive friction, moreover, hampers the action of the rotation mechanism whereby the drill steel is shifted to new positions between blows of the percussive element and the efliciency of the drilling apparatus is, therefore, materially lowered.

It is accordingly an object of the invention to stabilize the cutting end of the working implement and to assure its coincidence with the iongitudinal axis of the rock drill actuating it.

Another object is to enable the centralizer to be readily removed from its guiding position by the rock drill after the drill hole has progressed to a point at which the guiding function of a centralizer is no longer required.

Another object is to enable the centralizer to be expeditiously placed in the guiding position.

Other objects will be in part obvious and in part pointed out hereinafter. g

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts,

Figure 1 is a longitudinal side elevation of a centralizer constructed in accordance with the practice of the invention and a portion of rock drilling apparatus to which it is applied,

Figure 2 is an end elevation of the centralizer taken through Figure 1 on the line 2-2, and

Figures 3, 4 and 5 are transverse views taken through Figure 1 on the lines 33 4-4 and 5-5.

Referring more particularly to the drawing, 20 and 2| designate the front ends of a rock drill and a shell, respectively, and 22 a drill steel the shank of which may extend into the front head 23 of the rock drill to receive the blows of a hammer piston (not shown). On the opposite or free end of the drill steel 22 is a cutting bit 24 which may be of conventional shape for drilling holes into the rock 25.

The rock drill has the usual guide ribs 26 which extend slidably into guldeways 21 in the shell 2| to enable the rock drill to be advanced toward the work in accordance with the rate of penetration of the drill steel thereinto.

The centralizer constructed in accordance with the practice of the invention and designated in its entirety by 28 comprises an extension or support 29 which seats against the front end of the shell 2| and is secured thereto by bolts 30. On the opposite end of the extension 29 are a pair of lugs 3| through which and the extension proper extend eye-bolts 32 to support a yoke 33 having a bearing portion 34 for a guiding element 35 disposed about the drill steel 22.

The bolts 32 extend rearwardly of the extension 29 and carry nuts 35 to act as seats for springs 31 encircling the projecting ends of the bolts 32 and seating against the extension 29.

The eye-portions 3B of the bolts 32 lie forwardly of the extension 29 and accommodate a pin or bolt 39 which extends through the free ends of the yoke 33 to serve as a pivot for said yoke.. Adjacent. the free ends of the yoke and on the sides of its arms confronting the lugs 3| are seating surfaces 40 which engage the ends of the lugs 3|, in the operative position of the yoke 33, and are held thereagainst by the force of the springs 31.

The end surfaces of the arms of the yoke 33 and which are arranged angularly with respect to the surfaces 40 also constitute seating surfaces 3 4| adapted to seat against the ends of the lugs 3| in the non-guiding position of the centralizer.

The bearing 34 is located in the intermediate portion of the yoke 33. It has a bore 42 to receive a trunnion 43 on the guiding element 35 and the trunnion has a stem 44 upon which is threaded a nut 45 seating against the end of the bearing 34 to hold the trunnion 43 against endwise movement with respect to the bearing.

On the portion of the trunnion lying above the bearing 34 are a pair of diametrically opposed wings 46 which are integral with the trunnion and cooperate with stop members 41 on the adjacent end of the bearing 34 to limit the degree of rotary movement which the guiding element may describe with respect to the yoke 33. The

wings 46 and the stop members 41 are preferably so proportioned that the guiding element may be rotated through an arc of between the stop members.

The guiding element 35 is preferably an inte-' cal The guide arms are arranged on opposite sides of the bar 48' and are provided, on the sides confronting the drill steel 22, with partly annular recesses 58 to receive the body portion of the drill steel. The recesses 50 are concentric with the rock drill so that the drill steel will be retained coaxial therewith. irrespective of the degree of clearance between the drill steel and the chuck mechanism of the rock drill.

The guiding element 35 is normally held in the correct guiding position by a plunger 5| slidable in the bearing 34 and having a flatted surface 52 to engage a similar surface 53 on the portion of the trunnion 43 lying within the hearing 34. In the side of the plunger 5| and adjacent the surface 52 is a recess to accommodate the side of the trunnion in the non-locking position of the guiding element.

The plunger preferably extends entirely through the bearing 34 and is provided at its ends with heads 55 and 56 of which the latter head forms an abutment for a spring 51 encircling a portion of the plunger lying exteriorly of the bearing and seating against the bearing to normally maintain the plunger in the locking position. In the guiding position of the centraliz er the plunger lies in the path of movement of the front head 23 so that, as the rock drill advances toward the work, the front head will engage the head 58 and shift the plunger 5| for moving the surface 52 out of engagement with the surface 53 to release the guiding element 35.

To the end that the guiding element 35 may be quickly moved to the non-guiding position with- :5 out manual attention upon release of the plunger 5| from the trunnion 43 the centralizer is provided with a coil spring 58 which encircles the contiguous portions of the trunnion 43 and the bearing 34 and has one end interlocked with the bearing and its other end with the trunnion.

In the operation of the device, whenever it is desired to start a new drill hole the yoke 33 is rocked to the position shown in Figures 1 and 2 in which the surfaces 40 seat against the ends of the lugs 3|. The guiding element 35 is then rotated to bring the guide arms 49 into guiding position on opposite sides of the drill steel 22 and to place the spring 58 under tension. The spring 51 will then move the plunger to bring the surface 52 into engagement with the surface 53 thereby locking the guiding element.

The parts comprising the centralizer remain in these positions during the ensuing progress of the cutting bit 24 into the rock, and when the 5 front end of the rock drill contacts the button 56 the plunger 5| is shoved forwardly until the surface 52 is moved out of engagement with the surface 53. The trunnion 43 is then released and the spring 58 will expand and rotate the guiding element a quarter turn to move the guide arms out of guiding position.

As the rock drill continues its forward movement it will rock the yoke 33 and the parts attached thereto about the pivot 39 and thus out of the path of movement of the drill. In this position of the centralizer the surfaces 4| of the yoke will seat against the front ends of the lugs 3| and the drill maythereafter continue operation and its advancing movement until the working implement has penetrated the rock to the limit of its extent- The centralizer may remain in non-guiding position until another drill steel has been substituted for the starting steel and may, ihdesired, be again rocked to the guiding position to stabilize the overhanging portion of the new drill steel.

From the foregoing description it will be readily seen that by means of the present invention the cutting bit of the drill steel will be held coaxial with the rock drill so that when the bit encounters abnormalities in the rock the steel will be held against departure from the desired course. This is. particularly desirable and ad vantageous in drilling operations wherein it is essential that the holes be drilled in parallelism, as for example where the line of cut or drilling is later traversed by a breaching mechanism for removing material between adjacent holes.

I claim:

1. A centralizer for drill steels, comprising a bearing, a guide member journaled in the hearing, and a spring connected to the bearing and the guide member to shift the guide member from guiding to non-guiding position.

2. A centralizer for drill steels, comprising a bearing, a guide member journaled in the bearing, locking means for retaining theguide memher in guiding position, and a spring connected to the bearing and the guide member exerting a constant force on the guide member for shifting the guide member from guiding to non-guiding position upon release of the locking means.

3. A centralizer for drill steels, comprising a bearing, a guide member journaled in the hearing, locking means in the bearing to engage the guide member for holding the guide member in guiding position, and a spring connected to the bearing and the guide member constantly acting to shift the guide member from guiding to nonguiding position.

4. A centralizer for drill steels, comprising a bearing, a guide member journaled in the bearing, locking means in the bearing movable into and out of engagement with the guide member to lock the guide member in guiding position and to release the guide member, and a spring to shift the guide member to non-guiding position upon release of the locking means from the guide member.

5. A centralizer for drill steels, comprising a support, a bearing pivotally mounted on the support, a guide member having a trunnion journaled in the bearing, a spring-pressed plunger in the bearing movable into and out of engagement with the trunnion to lock the guide member in guiding position and to release the guide member, and a spring connected to the guide member and the bearing to shift the guide member to non-guiding position upon release of the plunger from the trunnions.

6. A centralizer for drill steels, comprising a support, a bearing pivotally mounted on the support, spring means for maintaining the bearing in the correct operative relationship with the support, a guide member having a trunnion journaled in the bearing, a plunger movable into and out of engagement with the trunnion to lock the guide member in guiding position and to release the guide member, a spring acting to maintain the plunger in engagement with the trunnion, and a spring to move the guide member to nonguiding position upon release of the plunger from the trunnion.

JOSEPH I. HULSHIZER. 

